In competitive rowing in sweep rowing shells and sculling shells with more than one rower, the rowers train so that they all execute the stroke in unison. The rowers are evenly spaced to provide enough room for sliding back and forth on the slides and rowing without impeding one another. Typical spacing from oarlock pin to oarlock pin measured along the lengthwise axis of the boat for adjacent rowers is 1.4 m. Rowing a boat in unison results in considerable variation in the boat's velocity during each stroke. It has been determined that a boat's velocity ranges from about 25% greater than the average velocity to about 25% less than the average velocity during each stroke cycle and the time averaged velocity is approximately 12% greater than the average velocity half of the time and approximately 12% less than the average velocity half of the time. (“The FISA Coaching Development Programming Course”, Level 1 Handbook (revised 1990), Section 3, page 3, editors Thor Nilsen, Ted Daigneault and Matt Smith). The resistance for moving a boat through the water is approximately proportional to the velocity of the boat squared and the power required to maintain a particular velocity is approximately proportional to the boat's velocity cubed (“Physics of Rowing,” Dr. A. Dudhia, Department of Atmospheric Physics, Oxford University, dudhia@atm.ox.uk). Therefore, it requires approximately 4% less power to propel a boat at a constant velocity (Vc) than for a boat with the velocity half of the time at 12% greater than Vc and half of the time at 12% less than Vc, if all other factors remain the same. This patent describes a method for rowing boats with two, four, or eight rowers to reduce the stroke cycle velocity variation and thereby to increase the velocity/power efficiency. The patent also describes changes in boat design to facilitate rowing in a manner to reduce the stroke cycle velocity variation.
The method described in this patent is referred to as stroke cycle phase shift rowing. Boat designs are specified to facilitate individual rowers or groups of rowers, rowing out of phase with other individual rowers or groups of rowers. Phase shift rowing, previously referred to as syncopated rowing or multicycle rowing, was mentioned in the “Textbook of Oarsmanship” by Gilbert Bourne (1925). Bourne states that, “Mathematicians frequently assure me that, if only we could rig out and train a crew that one pair of oars was always at work, the boat would go much faster. An oarsman can only plead his experience in mitigation of his ignorance of mathematics and say politely that he is quite sure it would not.” In “The Story of World Rowing” by Christopher Dodd (1992) the author notes that syncopated rowing was tried by F.E. “Two legs” Hellyer in the 1930s at the London Rowing Club using six men in an eight and that it failed. Other references and trials similarly indicate that syncopated rowing was tried and that it failed. Employing the designs and methods for phase shift rowing described in this patent will increase the velocity/power efficiency for rowing shells with slideable seats and will result in faster boats in competitive rowing.